http://tools.qhex.org/ - a whole lot of general Hunt tools - use this! +++++

https://nutrimatic.org/ - Matches patterns against a dictionary of words and phrases mined from Wikipedia, very useful for phrases which qhex struggles with

http://www.npinsker.me/puzzles/crossword - crossword parser, paste an image, get a spreadsheet back

https://images.google.com/ - Drag and drop images to reverse image search

http://wordsmith.org/anagram/ - anagram generator (note: this often goes down during Hunt)

http://quipqiup.com/index.php/ - cryptogram solver

http://planetcalc.com/1434/ - Caesar shifts

http://www.math.tamu.edu/~dallen/hollywood/breaking/v.htm - Vigenere encryption

http://www.onelook.com/ - dictionary with wildcard search

http://www.onelook.com/reverse-dictionary.shtml - Reverse dictionary

https://scrabblehelper.googlecode.com/svn-history/r20/trunk/ScrabbleHelper/src/dictionaries/sowpods.txt - scrabble tournament word list (SOWPODS)

http://devjoe.appspot.com/huntindex/keywords - Most, if not all, previous mystery hunt puzzles by keyword

http://www.oneacross.com - crossword solver. kinda shitty but better than nothing

https://www.tineye.com/ - Reverse image search. (Can also be done with google images)

https://www.google.com/ - you’d be surprised how many puzzles have been solved by random googling +1

http://www.visca.com/regexdict/ Regular expression dictionary